1. Field of the Invention
The present invention relates to a developing apparatus used for image forming apparatuses such as monochrome or color copying machine and printer. More particularly, the present invention relates to a developing apparatus and an image forming apparatus using this wherein developer leak and defective supply of developer caused by partial agglomeration of developer are prevented by removing agglomerates of developer.
2. Description of the Prior Art
An image forming apparatus for a copying machine and a printer forms an image on a recording medium as follows. That is, an image forming apparatus gets surface of a photosensitive drum charged at first, then, the charged surface receives exposure to light and forms an electrostatic latent image thereon. Next, a developing apparatus lets developer adhere to the electrostatic latent image on the surface of the photosensitive drum to obtain a toner image. After that, the developing apparatus transfers the toner image onto a recording medium.
In the developing apparatus, developer is supplied from a supplying member to a developer carrier. Then, a regulating member regulates thickness of developer layer on the developer carrier to make the developer layer constant and thereby, extra developer is removed therefrom. Such developing process is carried out so that an image formed on a recording medium should have predetermined density.
When non-magnetic one-component toner type developer is used for development, pluralities of developer particles sometimes gather together and form agglomerates of developer which are several ten times as large as singularity of particles in size. When the agglomerates stop at a space between the regulating member and the developer carrier, the regulating member is partially raised by the agglomerates. As a result, the space between the regulating member and the developer carrier is partly widened. From the widened portion, developer leaks because developer exceeding inherent regulated thickness of developer passes through the widened portion and is carried onto the developer carrier. The agglomerates themselves stop at the space and prevent developer from passing therethrough. Thereby, defective supply of developer occurs at the downstream for the developer carrier in rotating.
Conventionally, there have existed measures to rotate a developer carrier in a reverse direction and thereby, agglomerates stopping at a space between a regulating member and a developer carrier can be removed therefrom. However, such measures only aim to remove the agglomerates from the space. Therefore, the removed agglomerates are likely to stop at the space again and all efforts to remove the agglomerates from the space go for nothing after all.